The prior art is replete with scores of patents which describe various vibratory conveyor systems which are utilized to convey a product along a course of travel for various purposes.
These vibratory conveying systems, as exemplified in U.S. Pat. No. 4,313,535, and incorporated by reference herein, have traditionally been utilized for transporting a stream of articles from one point to another in a production line. Such vibratory conveying systems have found acceptance in many industries, and have received exemplary acceptance in the food production industries. This acceptance in the food industry is understandable given the reputation of superior sanitation afforded by vibratory conveying systems over alternative conveying technologies.
An important application of vibratory conveying systems includes the combination of transport and distribution of articles from a single incoming product stream to multiple product streams. In this application, the vibratory conveying systems include metering stations or gate assemblies that are integrated into the vibratory conveyor at points along the length of the conveyor to selectively divert or transport all or a portion of the stream of articles from the vibratory conveyor to a downstream conveyor, chute, or another machine. This transfer of the articles is most often accomplished by virtue of gravity. The metering stations or gate assemblies may be operated by either manual or powered means, and may be controlled manually or automatically. Most manual metering stations are operated in a transverse manner by movement of a slide or gate plate to selectively cover apertures formed in the pan or trough of the vibratory conveyor. Most automatic gate stations are operated in a longitudinal manner to selectively cover apertures formed in the bed of the vibratory conveyor.
Many automatic or powered gate stations found in the market today operate exclusively in one of two discrete positions—either fully open or fully closed. An example of such a gate station is shown in U.S. Pat. No. 6,945,382 and incorporated by reference herein.
For many years, several automatic metering stations have been available that are capable of selecting a portion of the stream of articles by selectively blinding a portion of the aperture formed in the bed over a range between the fully opened and fully closed positions. One exemplary example of this type of metering station is the transverse metering station found in U.S. Pat. No. 5,555,967 and incorporated by reference herein. This metering station provides a slide plate that is selectively movable in a transverse direction past a plurality of apertures to proportion or meter articles from a product stream. In this case, the slide plate is movable by a motorized actuator mounted on the quasi-stationary member of the vibratory conveyor, in this case the frame of the vibratory conveyor, and connected via a linkage.
The motorized actuators used in proportioning or metering gates in much of the prior art are mounted to the frame of the vibratory conveyor and coupled to the slide plate by a linkage. This frame mounting arrangement and linkage serves to isolate the motorized actuator from the violent vibrations that would be experienced if the motorized actuator was mounted to the bed of the vibratory conveyor. However, such linkage arrangements introduce additional problems including inaccuracy, backlash, linkage failure, and sanitation problems.
In addition, the motorized actuators themselves require a rotational to linear converter which often takes the form of a lead screw of suitable length to provide for movement of the slide plate to cover the extent of distance needed to open and close the gate. Such lead screws require maintenance and are similarly prone to introducing sanitation problems which are especially problematic in food production environments.
So, what is needed is a vibratory system for distributing articles or a vibratory distribution system that is a robust and sanitary metering or proportioning gate or metering station that installed in a vibratory conveyor that is able to accurately divert or distribute articles in a controlled ratio and manner. These and other objects and advantages of the present invention will become apparent upon careful consideration of the following description of the invention.